Some few names can be derived from the runic inscriptions on the Crosses.
Few Manx names are preserved in documents prior to the coming of the Stanleys in 1405 - a Declaration of the Bishop, Abbot, Clergy and Keys in 1408, an Indenture of 1417/8 gives the name of the Keys and a document of 1422 gives a list of the 'great and the good'. W.W.Gill makes reference to, and quotes extensively from, a Sheading Court Roll for Rushen covering the year 1417/18 which was exhibited in 1877 [current whereabouts appear to be unknown].
The majority of early family names are those found in the first of the Manorial Rolls dating from 1510-1513 - these were transcribed by the Rev T. Talbot and published posthumously in 1924. Gill and others have commented that
The spelling of personal names in the first Manorial Roll, by the way, seems to have been partially standardised, in a way very unusual if not unique at that date, by someone with theories on the subject. It is impossible otherwise that MacWhaltragh, MacJoghen, MacTere, MacKerron, MacAulay, MacCorkell, MacCorleot, all the MacGil prefixes, and many other names, each from various parts of the Island, could have been spelt with such strict uniformity, in striking contrast with those in other documents of all dates previous to the 19th century, where the variations show that the orthography rested largely on the usual phonetic basis.
Gill comments of the great number of the early names showing connection with Lancashire and the Stanly Estates centred around West Derby.
These date from around the beginning of the 17th century - names of the same person can be spelt differently within the same entry - as for the most part people were illiterate until quite late in the 18th or early 19th centuries the names represent the vicar's, or parish clerk's attempt to transcribe them phonectically.
For some discussion see A.W. Moore's introduction to Manx surnames.